Description
A vulnerability in the handling of certain Ethernet frames in Cisco IOS XE Software for Catalyst 9000 Series Switches could allow an unauthenticated, adjacent attacker to cause an egress port to become blocked and drop all outbound traffic. This vulnerability is due to improper handling of crafted Ethernet frames. An attacker could exploit this vulnerability by sending crafted Ethernet frames through an affected switch. A successful exploit could allow the attacker to cause the egress port to which the crafted frame is forwarded to start dropping all frames, resulting in a denial of service (DoS) condition.
Affected products
cisco: ios xe; cisco: catalyst 9200; cisco: catalyst 9200cx; cisco: catalyst 9200l; cisco: catalyst 9300; cisco: catalyst 9300-24p-a; cisco: catalyst 9300-24p-e; cisco: catalyst 9300-24s-a; cisco: catalyst 9300-24s-e; cisco: catalyst 9300-24t-a; cisco: catalyst 9300-24t-e; cisco: catalyst 9300-24u-a; cisco: catalyst 9300-24u-e; cisco: catalyst 9300-24ux-a; cisco: catalyst 9300-24ux-e
References1
- sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAd… Vendor Advisory
Metrics
- CVSS 3.1
-
7.4
HIGH
Score source: CNA
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H - EPSS — exploit probability
- 0% percentile: 11 · as of 8 November 2026
- CWE
- CWE-19
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